The purpose of this broadly based multidisciplinary Training Program is to prepare graduate students for biomedical research careers in college and university basic science departments, Schools of Medicine and Public Health, and government public health research centers in the new emerging field of the population biology of infectious diseases. A major goal is to provide students with experience in both academic research departments and with clinical and public health applications of the population biology of emerging infectious diseases. The areas of expertise represented by the 25 training faculty include the mathematical modeling of infectious disease emergence and spread, the population dynamics and evolutionary genetics of antimicrobial resistance, the evolutionary biology and dynamics of the immune system, evolutionary origins of infectious disease agents, and the population biology of immunization and control of infectious disease. Training faculty are drawn from the Emory College, the School of Medicine, the School of Public Health, The Vaccine Research Center, and the Centers for Disease Control and Prevention. The most important component of training is laboratory and/or field research, first as a series of three laboratory and/or field rotations among the training faculty, then in the dissertation laboratory or field site. The training is complemented by core courses in population biology, evolutionary biology, ecology, molecular evolution, and statistics and mathematical modeling. Advanced courses are offered in epidemiological modeling, biostatistics, bioinformatics, population genetics, molecular epidemiology, and specialized seminars. Emphasis throughout is placed on oral presentation skills;students make formal seminar presentations of their own work or review of the literature throughout their training in regularly scheduled seminars and journal clubs. The Program is designed to support six students for each of five years. Primary emphasis will be placed on supporting students during the first two years of their training as they acquire the knowledge and expertise to choose an appropriate dissertation project and committee. RELEVANCE (See instructions): Most emerging infectious diseases are the consequence of either ecological or evolutionary change in the interaction between hosts and pathogens. The population biology of infectious diseases is an essential element in the training of research experts for predicting and forecasting patterns of disease emergence and spread and for providing tools for the control of infectious diseases.